LU-7412 osp_md_read() may pass an ERR_PTR() to osp_update_request_destroy()

LU-7412 osp_md_read() may pass an ERR_PTR() to osp_update_request_destroy()

In osp_md_read() if osp_update_request_create() fails with ERR_PTR()
it should return rather than passing on ERR_PTR() to the
osp_update_request_destroy()

Change-Id: Id4c0c5b3e0619a4e657c22bf27a5679e02164007
Signed-off-by: akam kumar bharathi <azurelustre@gmail.com>
Reviewed-on: http://review.whamcloud.com/17522
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: wangdi <di.wang@intel.com>